This invention relates to a blood collection assembly incorporating a microcollection container. The invention is an improvement over the collection assembly described and claimed in U.S. Pat. No. 4,397,318, issued Aug. 9, 1983, which is hereby incorporated by reference in its entirety. This invention is related, also, to the inventions described and claimed in co-pending U.S. patent application Ser. Nos. 743,250 now U.S. Pat. No. 4,653,512 issued Mar. 31, 1987 and 743,534 now U.S. Pat. No. 4,646,753 issued Mar. 3, 1987, both filed Jun. 11, 1985. Reference should be made to the patent and the applications for background information concerning the teachings of the invention here. The earlier patent involved the use of a scoop collector for connection to a blood microcollection container for engaging a puncture wound to obtain a blood sample from an individual for subsequent examination of that sample for the determination of the presence or absence of some disease or other problem in a patient. The scoop-type blood collection device provides a substantially larger engaging surface for engaging the puncture for collecting the blood, and a substantially larger transfer surface for rapidly transferring the blood from the collector into the microcollection container. Because of the relatively large engaging surface for engaging the puncture wound, the arrangement does not require a precise positioning of the scoop engaging surface in order to initiate and rapidly transfer a quantity of blood to the microcollection container.
As will be appreciated by practitioners-in-the-art, recent advancements in analytical instrumentation have made it possible to carry out a variety of hematological or chemical diagnostic procedures on very small quantities of blood. Because of this, a patient's finger, earlobe, or infant's heel may be punctured and a very small quantity of blood rapidly collected into a microcollection container for such testing. Such arrangements obviate the need to withdraw venous blood from patients. However, such collection arrangements must be such that the blood is rapidly collected prior to any coagulation thereof.
In the past, prior to the scoop collector disclosed in the above-noted U.S. Pat. No. 4,397,318, a cap or top arrangement was configured to fit on the top of a microcollection container with the top having an integral capillary tube for engaging the puncture and transferring blood to the container. However, with such an arrangement, the tip of the capillary tube had to be arranged precisely adjacent the puncture wound and the entire apparatus had to be so positioned that the blood flow along the bottom surface of the tubular microcollection container moved continuously in order to engage the surface of the container. Otherwise, if a precise positioning was not carried out, capillary action was not initiated or slowed with subsequent clotting. Such collectors are described in U.S. Pat. No. 4,024,857, issued May 24, 1977.
One problem with the scoop collector taught and claimed in U.S. Pat. No. 4,397,318, although the arrangement taught therein is highly efficient for the rapid collection of a blood sample into a microcollection container, is the fact that because of the very rapid collection of blood by the scoop collector, the separate blood passage in the collector becomes somewhat occluded by the blood passing therethrough and there is "hang-up" on the walls thereof by capillary action. While this phenomenon is only momentary, it can delay blood collection in situations where the technician is, for example, attempting to take a blood sample from a screaming, wiggly baby.
With this invention, by contrast, a separate or integral elongated blood flow inducing member is provided which serves as a guide for inducing blood flow passage along a surface, and as a bridge, inducing blood flow across a transition point between two parts in a blood collection assembly. Representative blood flow inducing members include, for example, an elongated rod or strip arrangement incorporated into a blood microcollection assembly in such a way that the collected blood is guided from the collector continuously into the associated collection container. For this reason, capillary action causing blood "hang-up" does not take place and blood flows rapidly through the collector into the collection tube or reservoir passage. This in turn reduces blood sample waste in the very small total quantities involved, resulting in a larger specimen yield. As a further feature of the invention here, in the blood collection tube, once a sample is collected there and the tube closed, the invention induces flow of the sample back and forth to enhance mixing of the collected sample with other components in the tube. Moreover, such an arrangement reduces the need for incorporating expensive wetting agents in the collector devices of the invention, either as a component of the material forming the devices or as a separately applied surfactant. Also, there is an avoidance of any reaction between the wetting agents and the sample being collected.
In order to enhance the movement of blood through the collector arrangements as taught in the above-noted patent and co-pending applications, this invention includes separate members such as rods or strips. Alternatively, elongated flow inducing members may be formed during the molding of the blood collection assembly parts. They are positioned in the collector and along the walls of the tube in which the specimen is taken. Thus, the invention induces sequentially, rapid flow in the collector, provides rapid bridging or transition of that flow from the collector to the tube wall, and finally, rapid flow along the tube wall to the bottom thereof.
As purely illustrative of materials and dimensions of the flow inducing member of the invention, a single film strip of flexible material comprised of polyethylene film may be 0.05 millimeters (mm) thick and 1.52 mm wide. A rigid polypropylene strip may be 0.25 mm thick and 0.91 mm wide. A solid rod may be comprised of polytetrafluoroethylene and have a diameter of 0.76 mm. A tubeshaped strip may be comprised of glass with an O.D. of 0.91 mm. The length will vary depending upon the different applications to be described below.
The elongated flow inducing members of the invention in the form of integral or separate rods, strips or indentations provide a continuous flow inducing or guiding surface for the sample being collected from the initial puncture wound to the final reservoir and they may be separately formed, and either merely positioned or adhered to the walls of the objects involved, or they may be incorporated into the molds forming the objects themselves. As mentioned above, the invention may be in the form of flat strips, or they may be square, round, or semi-round objects in cross-section. In addition, they may take the form of indentations in the walls, for example, of a collection tube, or the collector.
Other objects and advantages of this invention will be apparent from the following description, the accompanying drawings and the appended claims.